搜索结果：Veterinary pathology

Abnormal tarsal posture in dogs may be associated with structural lesions such as common calcaneal tendon complex rupture, plantar-supporting structure injury, tarsocrural instability, or neurologic dysfunction; however, common calcaneal tendon rupture is typically associated with a plantigrade posture rather than the weight-bearing-dependent tarsal hyperextension pattern described in this case. A 3-year-old intact male Pomeranian developed bilateral weight-bearing-dependent tarsal hyperextension immediately after bilateral medial patellar luxation (MPL) surgery performed at another hospital. At our hospital, complete cranial cruciate ligament rupture of the right stifle and recurrent grade II MPL of the left stifle were identified. Right lateral fabellotibial suture stabilization using a LigaFiba® 75 lateral suture and crimp system, with supportive reapplication of a 0.8 mm Kirschner wire at the previous tibial tuberosity transposition site, and left trochlear block recession with capsular resection and imbrication were performed. No direct surgical treatment of either tarsus was undertaken. During follow-up after stifle stabilization, bilateral tarsal hyperextension progressively decreased and was no longer clinically observed by 5 months. This case suggests that bilateral weight-bearing-dependent tarsal hyperextension may occur secondary to proximal stifle pathology even in the absence of major structural tarsal instability, and that hyperextension may resolve clinically following stifle stabilization.

Background: Veterinary staphylococcal species, including the Staphylococcus intermedius group (SIG) and Staphylococcus schleiferi, colonize and infect companion animals (pets) and humans. This study investigated the longitudinal colonization prevalence of veterinary staphylococci among pets, their humans, and household environments to identify factors associated with carriage and to characterize antibiotic susceptibility trends. Methods: Children with community-onset Staphylococcus aureus skin and soft tissue infection (SSTI), their household contacts, and pets were enrolled in the "Staph Hygiene Intervention for Eradication (SHINE)" trial. At five study visits over 9 months, humans, pets, and household surfaces were swabbed for staphylococcal species detection and health information was collected. Results: The 104 households containing pets comprised 459 humans and 178 pets (136 dogs and 42 cats). Veterinary staphylococci were recovered from 110 pets (62%), 39 (9%) humans, and environmental surfaces in 55 (53%) households. SIG was the most commonly recovered veterinary staphylococci. Ninety percent of colonized humans were colonized with the same staphylococcal species as their pet. In multivariable analyses, dogs were more likely to be colonized than cats and a higher burden of environmental surface contamination was associated with pet and human colonization. The prevalence of methicillin-resistant veterinary staphylococci was low, but resistance to multiple other antibiotics was common among these methicillin-resistant isolates. Conclusions: Carriage of the same staphylococcal species and temporal colonization patterns between companion animals and their owners may suggest cross-species sharing, with the environment serving as a reservoir.

Injuries of the metacarpophalangeal joint are a major cause of morbidity and catastrophic fracture in racing horses, yet early osseous pathology is often difficult to detect using conventional imaging. This pilot study aimed to correlate sodium fluoride Positron Emission Tomography (18F-NaF PET) radiopharmaceutical uptake with gross and histopathologic changes in the distal third metacarpal bone (MC3) and proximal first phalanx (P1). Five horses (three racing Thoroughbreds with fetlock injury and two non-racing controls) underwent ante-mortem 18F-NaF PET and cone-beam CT imaging (CBCT), followed by post-mortem gross and histologic examination of predefined anatomic sites. Quantitative PET measures, including maximum standardized uptake value (SUVmax), SUVratio, and PET grade, were compared with gross pathology and histopathologic scores for cartilage and subchondral bone. While there were significant regional correlations between PET metrics and gross or histologic scores at select sites, our results need to be considered in light of the small number of horses evaluated. Correlations between PET metrics and gross pathology score were identified on the distal metacarpus on the lateral dorsal condyle and on proximal P1 for lateral dorsal and mid-P1. Correlation of PET metrics and hyaline cartilage histopathology scores were found for dorsal medial and lateral P1, parasagittal dorsolateral P1 and the medial parasagittal groove of MC3. Correlation of PET metrics and histologic subchondral bone scores were significant for medial palmar condyle, medial parasagittal groove, and parasagittal palmar lateral of MC3. For P1, PET metrics and histologic subchondral bone scores were significantly correlated for parasagittal mid-lateral and medial dorsal regions. Overall, these findings demonstrate that 18F-NaF PET identifies localized bone remodeling that corresponds to histologic and gross pathology at specific fetlock regions, supporting its utility for detecting osseous injury, although relationships varied by anatomic location. Further work with larger numbers of horses is needed.

Magnetic resonance imaging (MRI) is one of the most common diagnostic modalities used in veterinary neurology and neurosurgery. MRI scans are an essential component of the comprehensive management of central nervous system neoplasms in companion animals. Because of the popularity and widespread use of MRI, veterinary pathologists and anatomic pathology trainees can benefit from understanding the fundamentals of MRI scans and how they can be applied to complement diagnostic neuropathology. Here, we review basic principles of MRI generation and terminology and discuss diagnostic imaging and correlative gross neuropathologic features of intracranial neoplasms of dogs and cats. As an exhaustive review of the MRI characteristics of the neoplasms reported to affect the central nervous system of dogs and cats is beyond the scope of this article, we will focus on the most commonly diagnosed intracranial tumors in these species.

Pathology of the cervical spine is an important cause of poor performance in sport horses. Computed tomography (CT) and magnetic resonance imaging (MRI) have improved musculoskeletal diagnostic capabilities. CT is well-suited to assess osseous pathology, although it is limited for assessing soft tissues. MRI, the gold standard for imaging soft tissues, cannot be used for antemortem imaging of the equine cervical spine. The diagnostic potential of CT for evaluating soft tissues of the equine cervical spine compared to MRI is not well-defined and warrants investigation. Postmortem MRI was performed on eighteen horses euthanized for clinical and CT myelographic findings of cervical disease. Synovial and vertebral nerve tissue abnormalities were graded on MRI and CT. Grading of radiologists' confidence in identification of synovial tissues and vertebral nerves on MRI and CT was performed. Hounsfield unit (HU) measurements of synovial and vertebral nerve tissues were recorded. MRI was superior at evaluating, and radiologists had greater confidence in MRI for identifying synovial and vertebral nerve tissues. Agreement between measurements of HU was variable and poorest for vertebral nerves. Findings support MRI's superiority for the evaluation of equine cervical vertebral nerves and synovial tissues. Caution should be exercised when interpreting CT findings of these tissues of horses.

The influenza A virus (IAV) has been responsible for multiple seasonal epidemics and poses a pandemic threat, and the growing number of variant strains constitutes a persistent threat to humanity. This study aimed to identify anti-influenza compounds from a traditional Chinese medicine (TCM) monomer library using a machine learning approach, with calmodulin as a hypothesis-driven target. The antiviral efficacy of the compounds with the highest predicted binding scores from virtual screening was evaluated using integrated computational and experimental approaches. A pre-trained protein language model (ConPLex) was employed for virtual screening. Molecular docking was used to predict binding characteristics, and network pharmacology was applied to generate hypotheses on multi-target mechanisms. The cytotoxicity and anti-H1N1 activity of the selected compounds were assessed in vitro, followed by in vivo evaluation of survival, lung pathology, viral load, and inflammatory mediators in a lethal mouse infection model. Sodium deoxycholate (NaDC) and deoxycholic acid (DCA) were identified as promising lead compounds. Both exhibited dose-dependent inhibition of viral replication in vitro with low cytotoxicity. Treatment with NaDC and DCA significantly improved survival rates and reduced lung pathology in H1N1-infected mice. Treatment was associated with suppression of nuclear factor kappa-B (NF-κB) activation, reduced pro-inflammatory cytokines, and elevated interleukin-10 (IL-10) levels. Molecular docking predictions indicated that NaDC and DCA exhibit moderate binding affinity for calmodulin, with binding energies of -8.38 kcal/mol and -7.61 kcal/mol, respectively. Furthermore, network pharmacology analysis suggested that these compounds may modulate pathways related to viral infection, inflammation, and immune regulation. NaDC and DCA demonstrate anti-influenza activity both in vitro and in vivo, reducing viral replication and alleviating inflammatory lung injury. These findings position NaDC and DCA as promising lead compounds for anti-influenza drug development and provide a foundation for further mechanistic validation.

Expression of the Csf1r gene is regulated by a conserved enhancer, the fms-intronic regulatory element (FIRE). In mice with a germ-line deletion of FIRE (Fireko) CSF1R expression is undetectable in bone marrow progenitors and classical monocytes but monocytopoiesis and non-classical monocyte maturation are unaffected. The loss of CSF1R is overcome in part by CSF2 in vitro and inflammatory recruitment in vivo. Fireko mice lack microglia and subpopulations of tissue-resident macrophages in peritoneum, kidney, heart, adipose, liver, skeletal muscle, pancreas, pituitary, adrenal and gonads. Heterozygous mutation impacts CSF1-induced proliferation and postnatal expansion of tissue macrophages. Physiological functions of heart and kidney were not affected by the absence of macrophages. In a model of renal injury macrophage recruitment and histopathology in WT and Fireko mice were indistinguishable but there was a male-specific increase in serum creatinine and urea in the Fireko. Tissue-resident macrophages depleted in Fireko mice, including microglia, were replaced by donor-derived cells following intraperitoneal transfer of wild-type bone marrow at weaning. The Fireko mouse provides a platform to dissect functions of tissue resident macrophages in development, homeostasis and pathology.

This study evaluated the effects of ammonia exposure on the physiological responses, vitality, and histopathology of Pangasianodon hypophthalmus at two temperatures. A 2 × 2 factorial design was applied using two total ammonia nitrogen (TAN) levels (0 and 10 mg/L) and two temperature regimes (28 °C and 32 °C) over a 4-week period. At the end of the experiment, clinical signs, histopathology, hematology, stress indicators (glucose and cortisol), liver function enzymes, and oxidative stress markers (malondialdehyde levels and antioxidant enzymes) were assessed. Fish exposed to 10 mg/L TAN at 32 °C exhibited severe clinical signs, including dermal erosion, muscle necrosis, and respiratory distress. Ammonia exposure at 32 °C significantly reduced red blood cell (RBC) counts, hemoglobin, and hematocrit. Furthermore, elevated temperatures exacerbated ammonia-induced stress, evidenced by significant increases in cortisol, blood glucose, and malondialdehyde levels, alongside altered liver and antioxidant enzyme activities. Histopathological analysis confirmed significant damage to the gill filaments, hepatopancreas, and renal tissues, with severity increasing alongside water temperature. These results indicate a synergistic effect between ammonia exposure and water temperatures, where higher temperatures reduce the threshold for ammonia tolerance, triggering respiratory distress, systemic oxidative stress, and metabolic failure. These findings underscore the critical need for strict water quality management in tropical aquaculture, particularly in regions like Egypt, as rising global temperatures due to climate change may transform currently sub-lethal ammonia levels into potent lethal stressor for P. hypophthalmus. However, the study is limited by controlled laboratory conditions and relatively short experimental duration, suggesting the need for long-term investigations.

Monitoring chemical residue levels in foods of animal origin is essential to ensure food safety and protect consumer health. Sulfites are commonly used in crustaceans to preserve quality; however, excessive levels may raise public health concerns, particularly for sensitive individuals. This study aimed to assess the compliance of shrimp from offshore and coastal fisheries in Morocco with current regulatory standards. A total of 60 samples were collected and analyzed for residual sulfite levels using the semi-quantitative strip test method. The results showed that sulfite concentrations ranged from 5 to 100 mg/kg in offshore samples, with a mean value of 41 mg/kg. Higher concentrations were observed in coastal samples, with an average of 172 mg/kg. Despite the observed differences between fishing origins, most samples complied with the established regulatory limits. These results support the importance of systematic monitoring programs within the fisheries supply chain to strengthen food safety control and contribute to veterinary public health protection.

Helicobacter pylori (H. pylori) infection is one of the major causes of gastric cancer and remains an important global health concern. However, the biological processes linking chronic infection to malignant transformation are still not fully understood. Unlike previous reviews that mainly emphasized oxidative injury or individual virulence factors, this review synthesizes current evidence into an integrated redox-centered framework for gastric carcinogenesis. This framework links signaling pathways, epithelial adaptation, diagnostic interpretation, and therapeutic stratification. Current evidence indicates that persistent redox imbalance interacts with inflammatory signaling, mitochondrial dysfunction, metabolic reprogramming, epigenetic alteration, microbiome disruption, and oncogenic pathway activation throughout disease progression. Particular attention is given to the coordinated roles of NF-κB, STAT3, PI3K/AKT, HIF-1α, β-catenin, and Hippo-YAP signaling pathways. These pathways contribute to epithelial survival, chronic inflammation, genomic instability, and malignant transformation. This review additionally introduces a conceptual threshold model describing the progression from early epithelial stress to increasingly stable oncogenic reprogramming during long-standing infection. In addition, the limitations of conventional infection-centered diagnostics and non-selective antioxidant therapies are critically discussed. Emerging diagnostic approaches include oxidative injury biomarkers, transcriptomic and epigenetic profiling, artificial intelligence-assisted pathology, and multi-parameter predictive models. These approaches may improve risk stratification and facilitate earlier identification of high-risk gastric states. The translational implications further emphasize the importance of stage-specific and compartment-directed therapeutic strategies, particularly selective redox modulation and precision-guided targeting. Overall, this review provides a multidimensional perspective on H. pylori-associated gastric carcinogenesis and highlights future directions for predictive diagnostics, mechanistic stratification, and precision-based therapeutic development.

Trichilemmal carcinoma (TC) is a rare cutaneous appendage malignancy with scarce human cases and very few animal cases have been documented in the available literature, especially in giant pandas. A 23-year-old male captive giant panda had 4-week scrotal hyperplasia and ulceration, with a 4.5 cm×4 cm irregular lesion and neutrophils were elevated. Pathology revealed dermal lobular/cord-like invasive atypical clear cells, squamous nests and outer root sheath cysts. PAS staining was positive. Immunohistochemistry showed Her-2 (+), CK5/6 (++), p63 (++), Ki-67 (+), CD34 (+), and p53 (+), excluding squamous cell carcinoma and trichofolliculoma. Local resection (0.8 cm margin) was done under general anesthesia. Postoperative anti-infection led to 2-week wound healing; 3-month follow-up showed no recurrence with normal behavior. This first reported giant panda TC with human-like immunophenotype provides evidence for managing rare animal cutaneous appendage tumors.

To address the lack of a commercially available vaccine for goose circovirus (GoCV), we developed and evaluated a prokaryotically expressed subunit vaccine targeting the viral capsid (Cap) protein. A truncated Cap protein (GoCV-ΔCap) was expressed in Escherichia coli (E. coli) and formulated with aluminum hydroxide as a subunit vaccine (GoCVsubvac). Goslings were primed intramuscularly (i.m.) with high (75 µg) or low (15 µg) doses GoCVsubvac, followed by a boost 14 days later. At 14 days post-boost, goslings were challenged with GoCV and were administered a bivalent inactivated vaccine against Newcastle disease virus (NDV) and H9-subtype Avian influenza virus (AIV). Using our established gosling pathogenicity model, vaccine efficacy was evaluated via body weight, lesions, viral load, antibody titers, cytokine responses, and interference with NDV/AIV immunity. Results demonstrated that the GoCV-ΔCap vaccine, especially the high-dose formulation, provided effective immunoprotection. It elicited robust humoral and cellular immune responses, reduced lymphoid pathology, and decreased the viral detection rate in lymphoid tissues from 100% (5/5) in infected controls to 40% (2/5). Importantly, it alleviated GoCV-induced immunosuppression and preserved the immunogenicity of co-administered vaccines. This novel subunit vaccine is a promising candidate for controlling GoCV disease (GoCVD).

Phaeohyphomycosis is an opportunistic fungal infection caused by dematiaceous fungi and is considered uncommon in dogs, particularly when associated with visceral or systemic involvement. Pulmonary disease as a primary site of infection is rarely reported in veterinary medicine and is often associated with an unfavorable outcome. This report describes a fatal case of pulmonary phaeohyphomycosis in a dog, characterized by severe granulomatous pneumonia, vascular invasion by pigmented fungal hyphae, and the development of large vessel thrombosis. Histopathological examination revealed septate, pigmented hyphae consistent with dematiaceous fungi associated with an intense granulomatous inflammatory response. Although molecular analysis by polymerase chain reaction was unsuccessful due to the absence of amplifiable DNA in archived FFPE tissue, the clinicopathological correlation and histopathological findings were sufficient to support a diagnosis consistent with phaeohyphomycosis. Severe pulmonary inflammation likely contributed to vascular endothelial injury, resulting in pulmonary hypertension and thrombosis of major veins. This case highlights the diagnostic and clinical challenges associated with phaeohyphomycosis in dogs and emphasizes the importance of considering this infection in the differential diagnosis of chronic or progressive respiratory diseases accompanied by systemic complications. Furthermore, it reinforces the relevance of histopathology and comprehensive clinicopathological evaluation when molecular confirmation of the etiological agent is not achievable.

A 7-month-old Belgian Malinois puppy was presented for progressively worsening ataxia and episodes of aggression. General physical examination was unremarkable, and neurological examination revealed ambulatory tetraparesis, spinocerebellar ataxia, thoracic limb pseudo-hypermetria, exaggerated head movements, bilateral vestibular signs and a bilateral divergent strabismus. A magnetic resonance imaging (MRI) of the brain and cervical spinal cord revealed a generalized cerebral atrophy. The dog woke up from anesthesia in a severe episode of disorientation and aggression, wherefore he was euthanized. Histopathology of the brain revealed diffuse and widespread oligodendroglial dysplasia with myelinated fibers disorganization. A disease-associated nonsense variant in NECAP1 (NC_049248.1:g.8636271G>A on chromosome 27), introducing a stop codon at codon 48 (XM_038576681.1:c.142C>T (p.Arg48*)) and truncating the only isoform by 83%, was identified by whole genome sequencing (WGS). The variant segregated in the affected family with a recessive mode of inheritance, but was not present in 158 undiagnosed Belgian Malinois from the Belgian population. The exact same variant, as well as another NECAP1 variant (c.301 + 1G>A), have been associated with early onset epileptic encephalopathy (EOEE) in humans, a disease that is characterized by intractable epileptic seizures and profound global developmental delay in young children. In conclusion, a previously unreported leukoencephalomyelopathy with oligodendroglial dysplasia causes spinocerebellar ataxia and abnormal behavior in Belgian Malinois.

Trypanosomiasis remains a major constraint to small ruminant production in sub-Saharan Africa, particularly among smallholder farmers. Although WAD goats are considered trypanotolerant because of their relatively low mortality during chronic infection, recent findings show that this survival is at the expense of reproductive efficiency. To back up this claim with scientific evidence, this review followed PRISMA guidelines and systematically searched PubMed, Scopus, and Web of Science for important studies published between January 1980 and February 2026. Search terms included African animal trypanosomiasis, Trypanosoma spp., WAD goats, reproductive dysfunction, trypanotolerance, oxidative stress, and hypothalamic-pituitary-gonadal axis. Of the 1245 retrieved articles, 14 met the inclusion criteria. Evidence from the included studies indicates that chronic trypanosome infection disrupts reproduction through interconnected mechanisms involving systemic inflammation, oxidative stress, endocrine imbalance, and impaired gonadal function. Available evidence suggests that T. brucei is frequently associated with ovarian dysfunction and embryonic loss, whereas T. congolense has been linked in some studies to uterine pathology and gestational reproductive disturbances. Female goats commonly exhibit irregular oestrous cycles, embryonic loss, and prolonged kidding intervals, while males develop impaired spermatogenesis, abnormal sperm morphology, and reduced testosterone levels. These reproductive impairments reduce kid output, milk yield, herd productivity, and household livelihood resilience. Integrated control strategies combining vector control, targeted chemotherapy, nutritional support, and selective breeding are essential for preserving both fertility and survival in trypanosome-endemic areas.

Under a One Health framework, viruses of veterinary and zoonotic importance pose significant threats to animal and human health, food security, and livelihoods, particularly in regions with intense human-animal interactions. In West Africa, despite recent advances in surveillance programs, important gaps remain in understanding viral diversity and cross-species transmission at wildlife-livestock interfaces. We conducted metagenomic surveillance to characterize viruses circulating across livestock, domestic animals, and wildlife in rural Ghana in 165 animals sampled across five regions. Viral RNA from serum and tissue samples was sequenced with the Illumina platform, and genomes were de novo assembled with MEGAHIT. Phylogenetic relationships were reconstructed using Bayesian approaches. We report the first genomic sequences of porcine parvovirus 3, canine parvovirus, rotavirus A genotype R16, and bovine hepacivirus subtype B from Ghana in over a decade. Phylogenetic analyses revealed intercontinental linkages between Africa and Europe for parvoviruses, persistence of hepacivirus lineages, and evidence of cross-species transmission for rotavirus. Notably, detection in apparently healthy animals highlights underrecognized circulation, gaps in vaccination effectiveness, trade-related biosecurity vulnerabilities, and the role of wildlife in viral maintenance and transmission. Our findings reveal dynamic viral diversity and connectivity across animal populations and ecological interfaces, emphasizing the fluid and interconnected nature of pathogen circulation within One Health systems. By integrating metagenomics and phylogenetics, this study provides a scalable framework for enhancing surveillance capacity, enabling the early detection of emerging threats and informing targeted strategies to mitigate zoonotic and economically important viral diseases in West Africa.

Smallholder sheep and goat production supports rural livelihoods and food security through the provision of meat, milk, hides and skins, employment, and household income in Malaysia. The control of gastrointestinal nematodes (GINs) in sheep and goats relies on routine deworming using albendazole, levamisole, and ivermectin anthelmintics. While these drugs are effective in reducing worm burden and improving animal productivity, prolonged and often indiscriminate use resulted in the emergence of anthelmintic resistance (AHR) in West Malaysia. Despite extensive evidence of AHR in GINs of sheep and goats in various production systems in Peninsular Malaysia, there is a significant knowledge gap regarding the status of anthelmintic efficacy of albendazole and ivermectin in GINs of sheep and goats in Sarawak. In this study, a preliminary experimental trial was conducted to evaluate the in vivo efficacy of albendazole and ivermectin using faecal egg count reduction test (FECRT) based on pre-treatment and post-treatment faecal egg counts conducted 14 days apart according to the updated World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P) guidelines for diagnosing AHR in ruminants. Coprocultures were also prepared from faecal samples collected post treatment to microscopically identify the third stage larvae (L3) of resistant nematodes using standard morphological criteria. The results of FECRT on albendazole showed a 76.8% (90% CI: 69.9-83.8) reduction in pretreatment epg in White dorper sheep (Group D) while ivermectin treatment showed 85.4% (90% CI: 80.8-89.9) in Barbados blackbelly sheep (Group A), 75.8% (90% CI: 65.3-86.3) in White dorper sheep (Group C), and 75.9% (90% CI: 65.7-86.1) in Saanen goats (Group B). Thus, all the treatment groups did not achieve the W.A.A.V.P recommended post treatment FECR for susceptibility (lower 90% CI ≥ 90% and upper 90% CI ≥ 99%) in sheep and goats, which has led us to reject the null hypothesis and conclude anthelmintic failure in GINs of sheep and goats in Sarawak. This study provides the first evidence of anthelmintic failure involving albendazole and ivermectin in sheep and goat farms in Sarawak. Further study using adjusted dose regime is required to clarify the status of ivermectin resistance in goats because metabolic factors rather than resistance may precipitate a lower efficacy when using standard sheep dose in goats. Nonetheless, this work provides preliminary data that lays a solid foundation for designing sustainable helminth control programs to overcome anthelmintic resistance in Sarawak.

Pancreas disease (PD), caused by Salmonid alphavirus (SAV), is a notifiable disease in Atlantic salmon (Salmo salar L.) in Norway. Conventional inactivated virus vaccines have shown variable effects in mitigating the disease, and a DNA vaccine has been used over the last 7-8 years, which may have resulted in the reduction in the number of reported PD cases. This manuscript provides a comprehensive overview of DNA vaccination in farmed fish, with a focus on the licensed DNA vaccine, Clynav®, against SAV3 infection. It explores the biological underpinnings of SAV infection, immune mechanisms activated by DNA vaccines, and the benefits and limitations of this approach. Although antigen processing and presentation mechanisms following DNA vaccination in fish remain incomplete, studies document robust innate responses and measurable adaptive immunity, including neutralizing antibodies, as seen in Clynav, and transcriptomic studies indicate that cell-mediated immunity is evoked under experimental conditions. Comparative trials demonstrate that DNA vaccination reduces viral load, tissue pathology, and, potentially, viral transmission, outperforming traditional oil-adjuvanted vaccines. Additionally, DNA-vaccinated fish show improved growth performance under field conditions. These findings support DNA vaccination as a promising strategy for controlling PD in salmon aquaculture, with implications for fish health, welfare, and sustainable production.

An Indo-Pacific bottlenose dolphin (Tursiops aduncus) in the coastal waters of Jeju Island, Republic of Korea, exhibited an oral mass and mandibular deformity over a documented 6-year period, including 3 years of intensive longitudinal monitoring by our research team. A multidisciplinary approach combining imaging, pathology, microbiology, and omics analyses was used to assess the dolphin. Post-mortem computed tomography confirmed a mandibular fracture at the oral mass site. Histopathological examination of the oral mass revealed prominent fibroblast proliferation and collagen deposition. Fibropapillomas and desmoid tumors were excluded based on viral detection assays and β-catenin accumulation analysis, supporting a diagnosis of trauma-induced fibroma. Transcriptomic analysis of the tumor tissues identified highly expressed genes associated with extracellular matrix remodeling, myofibroblast activation, and epithelial differentiation, supporting a reactive fibrotic rather than malignant phenotype. Gross necropsy revealed multiple suppurative pulmonary lesions, abundant foamy fluid within the respiratory tract, and diatoms within the pulmonary tissue. Metagenomic sequencing revealed a polymicrobial infection, with Parvimonas micra as the predominant organism. Collectively, these findings are most consistent with aspiration pneumonia, with severe secondary pulmonary infection considered a major contributor to death. In addition, analysis of halogenated organic contaminants revealed accumulation levels consistent with those typically observed in aged individuals, and no evidence was identified indicating a direct causal role in the terminal disease process. To the best of our knowledge, this is the first study to characterize the pathological features and proposed pathogenic mechanism of traumatic fibroma in a marine mammal, and the first confirmed case of pulmonary abscessation associated with Parvimonas micra infection in this taxonomic group. Overall, these findings provide valuable baseline data for the health monitoring and conservation of marine mammal populations.